In one form of V-belt power transmission mechanism, the V-belt is entrained about a driver pulley and a driven pulley so as to have side edge surfaces of the V-belt facially engaged complementary surfaces of the peripheral grooves of the pulleys. In one improved form of such a V-belt power transmission mechanism, the V-belt is provided with cogs in the lower portion thereof, providing improved flexibility and long life.
In such V-belts, there is a tendency for the lower portion of the belt to be deformed downwardly into the pulley groove during the power transmission operation, as illustrated in FIG. 1 of the drawing. This deformation results from a transverse enlargement of the belt resulting from the transmission of the drive forces between the belt and pulley, and one solution to the problem has been to provide in the inner, or compression, portion of the V-belt a plurality of transverse reinforcing fibers or elements.
In the manufacture of such belts, it is common to have the reinforcing fibers or elements exposed at the side edges of the belt where the belt comprises a raw edge belt, i.e. a belt that does not have a covering fabric on the side edges.
As the exposed ends of the reinforcing fibers or elements may engage the confronting sidewalls of the pulley grooves, wear of the sidewalls has resulted, thereby causing a number of problems in the prior art belts.
The engagement of the reinforcing element with the pulley sidewall surfaces increases the friction between the belt and pulley. The engagement tends to wear the pulley surface so as to develop circumferentially extending concavities adversely affecting the power transmission of the mechanism.
Such wear further makes it difficult to properly fit the belt in the pulleys and presents a problem in removal of the belt from the pulley, as during service and maintenance in that the concavities tend to prevent ready free withdrawal of the belt from the worn groove.
The wear of the pulley further causes the belt pitch line to fluctuate, thereby producing nonuniform stresses in the belt, again adversely affecting the useful life of the belt and the power transmitting capabilities thereof.
The engagement of the reinforcing fibers or elements with the pulley sidewall surfaces further has been found to create noise, such as creaks or beats, during the drive operation of the mechanism. In many applications, it is desirable to minimize noise and, thus, the known forms of such mechanisms have presented a serious problem in this regard.